Neuroscientists have become much more adept at creating the embryos of the human brain in a laboratory over the past few years. These'mini-brains,' which are now complex enough to allow us to study neurological diseases in their earliest stages.
Although the gray blobs are called brain organoids and cannot communicate with consciousness, they can provide information about the structure, diversity and interactions of cells in specific parts of the developing brain.
Researchers have compared brain organoids with the structure of a fetus’ brain after around a dozen weeks. Although they are unable to think, the little blobs can send tendrils to muscles and cause contractions. Although they cannot feel, they can create basic eye structures.
Scientists take a lot longer to reach even the most basic level of development than nature. It takes a lot of time to get stem cells from a human to multiply into millions and to grow into something that resembles a mini-brain.
It's not easy to maintain them. Brain organoids made from stem cells of Parkinson's patients have been grown for around 30 days. They've been grown for approximately 84 days in Alzheimer's disease.
Cambridge researchers have created a mini-brain the size of a pea to study amyotrophic lateral sclerosis. This is a huge step.
ALS is a neurodegenerative condition that causes rapid cognitive decline and paralysis. It often overlaps with frontotemporal degenerative dementia (ALS/FTD). Scientists don't know how it begins because the neurological symptoms usually appear later in life.
You can now see the lab-grown mini brain made from stem cells taken from patients suffering from ALS/FTD.
Growing brain-like clumps inside a dish is difficult because as the organoid expands, the cells in the middle are deprived of nutrients and cease to be useful models.
Researchers started to cut the organoids and then bathe them in culture a few years back. This allowed for their models to be preserved for longer periods of time and better study.
This was done by researchers at Cambridge using their early model for ALS/FTD. The team claims that they have grown organoids for a total time of 340 days in unpublished research.
The time period for which all the information has been published is 240 days. However, within that time frame, two types of brain cells were affected. Cell stress, DNA damage, and changes in how DNA is transcribed into proteins were all examples of these changes.
These destructive changes were seen in C9 neurons as well as another type of neural cell called astroglia, which are responsible for managing muscle movement and mental abilities in real brains.
"Even though these initial disturbances were subtle we were still surprised at how quickly changes took place in our human model of ALS/FTD," said Andrs Lakatos, a neuroscientist from the University of Cambridge.
"This study and others suggest that damage could begin as soon as we're born. More research is needed to determine if this is the case or whether organoids are accelerating the process by artificially enhancing the dish.
One of the most interesting results from the ALS/FTD model was the discovery that GSK2606414f, also known as GSK, could partially suppress certain neuronal changes that occurred early in cortex development. These included the clumping and stress of toxic proteins, the loss of nerve cells, and cell stress.
The authors state that similar drugs that are more suitable for humans are already being used in clinical trials to treat neurodegenerative diseases. They hope that their method of creating organoid models of neurological diseases will lead to further drug targets.
Lakatos explains that we currently do not have any effective treatments for ALS/FTD. He acknowledges that there are still many things to learn, but it does offer hope that the disease can be prevented or slowed down in the future.
"It might also be possible to take skin cells from patients, reprogram them to create their'mini brain', and then test which combination of drugs works best for their disease.
Although we are still far from this reality, it is clear that neuroscientists have made significant progress in just a few years.
Nature Neuroscience published the study.
